Games using a cellular phone terminal equipped with a GPS (Global Positioning System) have recently attracted attention. In the location game “Ichige” (registered trade name, No. 5302412 of COLOPL Inc.) of this kind, position information (latitude, longitude) is acquired for each predetermined time interval, the movement distance is calculated on the basis of a difference in position information between a large number of locations, and incentives such as points corresponding to the movement distance of the user that owns the cellular phone terminal are added.
Such location game “Ichige” (registered trade name, No. 5302412 of COLOPL Inc.) will apparently also generate a business of converting the points that have been acquired correspondingly to the movement distance into virtual currency for Internet purchases or mileage for transportation means. Therefore, it is necessary that the movement distance be calculated correctly.
A system for adding mileage points is disclosed in Japanese Patent Application Publication No. 2002-304563 (Patent Document 1).
Patent Document 1: Japanese Patent Application Publication No. 2002-304563
However, some users can perform fraudulent acts of intentionally extending the measured distance of the position information and acquiring a large travel distance by using poor reception (out-of-range) of the cellular phone terminal or by operating the movement distance by falsifying parameters assigned to the position information. Patent Document 1 does not address this issue.